Field of the Invention
The present invention relates to particles for a monolithic refractory which are made of a spinel porous sintered body.
Description of the Related Art
As a powder material that is a raw material for a monolithic refractory, various kinds of ceramic materials are often used, and in particular, in the light of heat resistance and corrosion resistance, alumina-spinel ceramics can be exemplified as a favorable form.
For example, JP 2002-187782 A discloses an alumina-spinel monolithic refractory, which uses an alumina material with purity of 99.5% or more, or preferably with purity of 99.7% or more for reducing generation of cracks and exfoliation so as to obtain high durability. Further, a spinel material with a total content of alumina and magnesia of 99.5% or more is used so as to reduce generation of cracks and exfoliation, thereby obtaining high durability.
By the way, as a material for a heat insulating material that can suppress rising of thermal conductivity in a high temperature region of 1000° C. or more and also has superior heat resistance, a magnesia-spinel ceramic porous body which is one of the forms of the alumina-spinel ceramics has attracted an attention.
Each of JP 2012-229139 A, JP 2013-209278 A and JP 2015-000838 A discloses that a spinel ceramic porous body having predetermined pore size distribution can suppress conductive heat transfer and radiant heat transfer, and thus can be used as a heat insulating material which has superior heat resistance even at a high temperature of 1000° C. or more.
Further, the applicant of JP 2012-229139 A, JP 2013-209278 A and JP 2015-000838 A and the present invention has filed an application of an invention that relates to a new monolithic refractory (Japanese patent application 2014-153565) on Jul. 29, 2014. This application aims to provide an unconventional monolithic refractory that utilizes the excellent thermal conductivity characteristics of the spinel porous bodies described in JP 2012-229139 A, JP 2013-209278 A and JP 2015-000838 A.
Moreover, the applicant of the present invention has focused on the possibility of obtaining a structure that has an unconventionally superior thermal characteristic by combining the above-described monolithic refractory with various kinds of existing refractories. Further, the applicant feels necessity to consider not only the combination with the various kinds of refractories for exhibiting the above-described superior effect, but also a favorable form of the spinel porous body which enables the monolithic refractory itself to exhibit the superior thermal characteristic.